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The exchange of CO2 and oxygen between the atmosphere and the groundwater is an important part of the water cycle. But no one knows how climate change affects groundwater quality. A new research project is intended to change that.

Most of us have learned about the water cycle in school—how water from the ground evaporates into the atmosphere, forming clouds, and returning to earth as precipitation, which seeps into the soil or evaporates. As a part of the cycle, gasses, CO2, and oxygen are exchanged between the atmosphere and the groundwater, which has a major impact on the amount and quality of groundwater, while also affecting many other factors such as the spread of pollution and nutrients. Rainfall and the extent of evaporation from the ground—two determining factors in the cycle—are influenced by the climate change currently taking place.

However, we know very little about how the exchange of gases is affected by the changes in temperature and wind speeds which we are currently experiencing. A new research project will provide more knowledge about this by imitating the new reality in a laboratory.

“In the laboratory, we use a large box to recreate a closed system with the entire cycle—atmosphere, soil, and groundwater. Then, under controlled conditions, we can measure how the exchange of gases is affected when we, for example, increase the temperature. The laboratory measurements are carried out using very delicate sensors which can register impacts during the process. Previously, we had to take samples along the way, which in itself can influence the cycle, while the samples can also be affected by the atmosphere when they are released. The new measuring method will therefore give us more precise and representative data than previously,” says Massimo Rolle, DTU Environment, who is in charge of the new research project GIGA, Gas Interchange between Groundwater and Air.
New knowledge to eliminate soil pollution
In addition to gaining knowledge about how the interaction between groundwater and atmosphere is affected by climate changes, Massimo Rolle’s research team will also focus on examining the role of micro-organisms—which, just like humans, consume oxygen and produce carbon dioxide—in the soil and groundwater throughout the entire process.

“In the long term, greater knowledge in this field may enable us to optimize the process of eliminating organic pollution on sites where petrol stations or industrial operations, for example, have previously been located. If it turns out that higher oxygen levels in the groundwater make the processes of microorganisms more efficient, we can actively use this knowledge to accelerate the work of bacteria and other microorganisms remedying polluted soil,” explains Massimo Rolle.

Welcome to DTU Environment. We work at the highest international level to develop new environmentally friendly & sustainable technologies and disseminate this knowledge to society and the new generations of engineers. Our activities in research, teaching and innovation are focused on: Air, Land & Water Resources, Environmental Fate & Effect of Chemicals, Residual Resource Engineering, Urban Water Systems and Water Technologies.